Alexander mckay



CENTRIFUGAL DRIER.

Application filed October 18, 1924. Serial No. 744,476.

To all wim/,1n t may concern:

Be it known that i, ALEXANDER hflolav, a subject oit the King of Great Britain, and resident oi the city o'i Montreal, in the Province ot Quebec and Dominion of Canada, have invented certain new and useful Improvements in Centrifugal Driers, ot which the following is a full, clear, and er;- act description.

yhis invention relates to new and useful improvements in driers and more particularly to centrifugal driers, and the object. ot the invention is to provide a device' which will quickly, thoroughly and inexpensively dry material such as sand, stone, ore, and other comminuted bodies.

Another object is to provide a drier of simple and durable construction, which will distribute the material to be dried into a thin uniform layer from which the moisture will escape readily.

A further object is to provide a driei` which by its construction will regulate the flow of material to be dried according to the moisture held by the material in its passage through the machine.

in my invention, li provide a drying col umn of cylindrical formation, which may consist of a plurality of flanged units bolted or otherwise secured to one another by their lianges. The top of the column is provided with a cover having an inlet for the materiel to be dried and an outlet for the spent heating or drying agent, which may be .suppned to the bottom of the column from a source (not shown). The lower part oit the column is provided with an inverted conical bot toni or hopper, having an outlet formed thereinto facilitate the removal oi the dried material. i'iecurely attached to a shaft rotat ably mounted in bearings formed in or secured to the cover and bottom of the column are a plurality ot discs, adapted to spread the material uniformly in the lorm ot a thin layer, so that the maximum amount of surface or' the material will be subjected to the maximum amount oi vheat during the prog ress of the material through the machine. The discs are graded to regulate and assist the iiow of the material through the machine. Baii'les or hoppers are also provided within the column to assist the drying operation of the material.

ln the drawing, have shown an elevation partly in section oit one embodiment or" my invention.

.lu this drawing, ll designates a i'ilurelitv oi column units preferably cylindrical and all exactly alike. The units maybe pro vided with lianges 1.2 through which bolts may be placed to hold the units together, so that as many units as desired may be assembled to Yform a drier column of any desired hei glit. rt the top oft the drier,there is provided a cover 13 carrying a bearing ld disposed substantially concentric-ally 'with the shell. The cover also carries a charging spout or chute l5 directed toward the axis ot' the device and an outlet stack 16 ior the spent Lheating agent and dust. rt the lower end ot the drier there is provided an inverted conical hottoin li', l'from the apex or lower point oit' which extends a discharging chute or conduit i8 or dried material. A heating agent, such ashot air, may be adA niitted anywhere at the lower end of the device but preferably through a conduit l@ connecting with the upper part of the conduit i8. The object ol this arrangement is 'to keep the mouth ot the conduit 19 'tree from obstruction by material passing through the drier. rlhe bottom also Acarries a bearing EEO disposed concentrically ot' the shell. 5r series ot inverted truste-conical chutes or hoppers 2l are provided, one above the other within the shell. yEhe chutes may cimveuieuilj," be secured by engagement ot their outer and upper edges between the lian oi adiacent column units. These are prcierablv made ot thin material. which will quickly absorb heat from the drying agent. 'lhey also iorni heat retain k pockets 2l lo retard the progress ot t heating agent through the drier, so that as much heat as possible may be absi'irbed by the various portions yot the drier trom the heating agent. l A plurality ot sha't't sections are provided, avi-all',Iv coincident' with the column and conveniently provided with. flanges QS for bolting` them together. The drier plates or pans 2d, 25. QS and 2T may be conveniently attached to the shaft by' holtingthem between the adjacent shaft sections. Obviously, the construction ot the shaft and the method ot attaching `the drier plates thereto may be varied as desired. The shaft is journalled in the bearings lf and Q0 to maintain it and the plates concentric with the shell, and may be supported and driven by any suitable means (not shown). The arrangement is preferably such that there is a drying plate over each hopper 21, considering the drier from the top downwards. At the bottom of the drier, the conical end 17 corresponds with and replaces the ordinary hopper. As will be clearly seen, the drier plates or discs are of smaller'diameter than the shell or column, while the hopper or chutes 21 are of the same external diameter and 'have central openings. The-drier plates 2a, 25, and 27 have their upper surfaces curved or dished vin a manner to provide elevated central and peripheral portions.' Comparing the plates,vit will be -noted that the'elevationof the central portion 28 of the plate 24 is slightly greater than the elevation of the central portion 29 of the plate 25. t will also be noted that the elevation of the central'portion v29 of theplate 25 is greater' than the elevation of the clentral portion 30 oftheplate 26, land that the elevation ofthe portion 30 is greater than the elevation of the centre portion 31 of the plate 27. lt will beseen that the plates are of different curvatures through the variation in the heights of their respective centre por tions, the plate at the top ot the column having the highest'centralportion, while the plate lat the bottom has the lowest central portion, the intermediate plates being -provided vwith central lportions varying in vheight between the highest and the lowest.

ln the drawing, I have shown only four plates, but this 'is for illustrative purposes only, and the number of plates fand corresponding hoppers may be increased or decreased .according to' requirements. It will be noticed that these drier plates `are made of thin material and provide a lrecessedportion under their centres. The recessed portions act as batlles'and retard the progress of the heating agent through the machine,so that the maximum amount of heat may -be utilized for drying the material as it passes through the machine. The edges 33 of the plates are turned upwardly to form a rim to spread and throw the material against the iside walls of the cylindrical column in a uni form manner.

The operation of the device is as follows Y iV arm air is fed into the device through 'the'conduit 19,*and is retarded in-its progress through the drying chamber by the `hojpers and drier plates. The air comes in contact with the underside of the plates, and is guided into the pockets 21 by the curvature of the rim, which prevents a direct flow of the heating agent through the apertures formed in thehoppers. This construction 'allows the hoppers and `drier platesvto absorb heat xfrom the heated air, in order to increase the efficiency of the ma chine. The shaft is rotated from a source (not shown). The material to be dried is fed into the drying chamber through the chute 15, in such a inanner that it falls at the centre of the uppermost drier plate. The material slides down into the grooved or dished portion of the plate against the sides ot the drier frame or column by means of the curved rim. The material in its passage to the frame describes an are and then falls on to the hopper immediately below the 'drier plate, said hopper being so positioned that it 'guides the material toward the centre ot theA drier plate immediately below the hopper, -from where it is again Athrown against the walls ofthe drier. fhis cycle of operation is repeated until the material leaves the lowcrmost disc, from where it falls into the discharge hopper 17 and through the pipe 18 to a storage bin (not shown). The material is thrown off the plates .by centrifugal action. The uppermost plate is provided with a high central portion to yassistthe initially damp mate` rial in its outward passage vfrom the plate, so that parts of the material thrown from the edge of the plate will tend to separate yand spread evenly 'from the edge of the plate. rThe material is also assisted in its separation by coming in contact with the innerwalls of the drier from where it is led on to the second drier plate by means of the hopper. The plates taken in order from top to bottom of the drier are gradually reduced in height with regard to their centre portions, as the material is gradually broken up and the lower discs are used more for spread-ing the material in a thin uniform layer than the ones immediately above them. This distribution of the-material is essential to allow the heat to come in contact with the grains of the material to thoroughly dry same. rhe gradual alteration of the heights "of the centre portions of the discs. also tends to regulateand assist the flow'of material through the drier, which is so constructed that the maximum amount of `heat is utilized for drying purposes, thereby iucreasing the eilicicncy of the machine. The drier column is provided with an outlet stack for dust and for the spent heating lagent. A

The device forms a simply operated device which quickly and ecoi'umiically dries materials, such as sand, stone, ore and other con'imiimted bodies.

Having thus described my invention, what l claim is 1. n a centrifugal drier, a drier column, a plurality of curved drier plates rotatably mounted ,in the centre of the column, such the highest centre portion being placed at the top of the column and the plate with the lowest centre portion being,` placed at the bottom of the column, with the heights of the centre portions oi the plates between varying` between the heights of the centre portions of the uppermost and lowermost plates, a plurality of inverted frusto-coni cal hoppers placed between each drier plate and mounted in the column and secured thereto, the plates and the hoppers being made of thin material and adapted to form pockets on their lower sides to provide battles tor a drying agent fed into the bot-tom oi' the column, said hoppers having?r their lower ends open and so positioned with reference to the drier plates as to deliver material on to approxin'iately the highest central portions of said plates, means positioned at the top of the column for feeding the material to be dried on to the centre ot the uppermost drier plate, means positioned at the bottom of the column for withdrawing` the dried material, and means for withdrawing dust and the spent heating agent from the column.

2. A device accordingl to claim 1, having the edges oi' the plates oit diilerent curvature turned slightly upwardly and adapted to overlie the central parts of the conical hoppers directly below them.

ln a centrifugal drier, a drier column, inverted conical hoppers mounted in said column, a plurality of dished drier plates rotatably mounted in the drier column, each plate being` dished to provide elevated central and peripheral portions, the central and peripheral portions ot the several plates be* ing made of varying` height, the plate with the highest central portion and shallowest peripheral portion being' placed at the top of the column and the plate with the lowest central portion and the highest peripheral portion being placed at the bottom ol the column, the arrangement being such that each plate is -formed with a central portion oit less height than the corresponding portion of the plate next above and with a peripheral portion of greater height than the peripheral portion ot the plate next above, and means tor rotating said plates including` a supporting* shaft connected therewith.

ln witness whereof, l. have hereunto set my hand.

ALEXANDER lilolillir. 

